[Backport 0.5] Abstract service for accessing Flint index metadata

docs/index.md

@@ -522,6 +522,8 @@ In the index mapping, the `_meta` and `properties`field stores meta and schema i
 - `spark.datasource.flint.auth.password`: basic auth password.
 - `spark.datasource.flint.region`: default is us-west-2. only been used when auth=sigv4
 - `spark.datasource.flint.customAWSCredentialsProvider`: default is empty.
+- `spark.datasource.flint.customFlintMetadataLogServiceClass`: default is empty.
+- `spark.datasource.flint.customFlintIndexMetadataServiceClass`: default is empty.
 - `spark.datasource.flint.write.id_name`: no default value.
 - `spark.datasource.flint.ignore.id_column` : default value is true.
 - `spark.datasource.flint.write.batch_size`: "The number of documents written to Flint in a single batch request. Default value is Integer.MAX_VALUE.

flint-core/src/main/scala/org/opensearch/flint/core/FlintVersion.scala → flint-commons/src/main/scala/org/opensearch/flint/common/FlintVersion.scala

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package org.opensearch.flint.core
+package org.opensearch.flint.common
 
 /**
  * Flint version.

flint-commons/src/main/scala/org/opensearch/flint/common/metadata/FlintIndexMetadataService.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.common.metadata;
+
+import java.util.Map;
+
+/**
+ * Flint index metadata service provides API for index metadata related operations on a Flint index
+ * regardless of underlying storage.
+ * <p>
+ * Custom implementations of this interface are expected to provide a public constructor with
+ * the signature {@code public MyCustomService(SparkConf sparkConf)} to be instantiated by
+ * the FlintIndexMetadataServiceBuilder.
+ */
+public interface FlintIndexMetadataService {
+
+  /**
+   * Retrieve metadata for a Flint index.
+   *
+   * @param indexName index name
+   * @return index metadata
+   */
+  FlintMetadata getIndexMetadata(String indexName);
+
+  /**
+   * Retrieve all metadata for Flint index whose name matches the given pattern.
+   *
+   * @param indexNamePattern index name pattern
+   * @return map where the keys are the matched index names, and the values are
+   *         corresponding index metadata
+   */
+  Map<String, FlintMetadata> getAllIndexMetadata(String... indexNamePattern);
+
+  /**
+   * Update metadata for a Flint index.
+   *
+   * @param indexName index name
+   * @param metadata index metadata to update
+   */
+  void updateIndexMetadata(String indexName, FlintMetadata metadata);
+
+  /**
+   * Delete metadata for a Flint index.
+   *
+   * @param indexName index name
+   */
+  void deleteIndexMetadata(String indexName);
+}

flint-core/src/main/scala/org/opensearch/flint/core/metadata/FlintMetadata.scala → flint-commons/src/main/scala/org/opensearch/flint/common/metadata/FlintMetadata.scala

@@ -3,14 +3,13 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package org.opensearch.flint.core.metadata
+package org.opensearch.flint.common.metadata
 
 import java.util
 
+import org.opensearch.flint.common.FlintVersion
+import org.opensearch.flint.common.FlintVersion.current
 import org.opensearch.flint.common.metadata.log.FlintMetadataLogEntry
-import org.opensearch.flint.core.FlintVersion
-import org.opensearch.flint.core.FlintVersion.current
-import org.opensearch.flint.core.metadata.FlintJsonHelper._
 
 /**
  * Flint metadata follows Flint index specification and defines metadata for a Flint index
@@ -35,7 +34,11 @@ case class FlintMetadata(
     schema: util.Map[String, AnyRef] = new util.HashMap[String, AnyRef],
     /** Optional latest metadata log entry id */
     latestId: Option[String] = None,
-    /** Optional latest metadata log entry */
+    /**
+     * Optional latest metadata log entry. TODO: remove? This was added for SHOW command to be
+     * fetched during get(All)IndexMetadata. Now describeIndex uses metadata log service to fetch
+     * log entry after get(All)IndexMetadata so this doesn't need to be part of FlintMetadata.
+     */
     latestLogEntry: Option[FlintMetadataLogEntry] = None,
     /** Optional Flint index settings. TODO: move elsewhere? */
     indexSettings: Option[String]) {
@@ -44,124 +47,10 @@ case class FlintMetadata(
   require(name != null, "name is required")
   require(kind != null, "kind is required")
   require(source != null, "source is required")
-
-  /**
-   * Generate JSON content as index metadata.
-   *
-   * @return
-   *   JSON content
-   */
-  def getContent: String = {
-    try {
-      buildJson(builder => {
-        // Add _meta field
-        objectField(builder, "_meta") {
-          builder
-            .field("version", version.version)
-            .field("name", name)
-            .field("kind", kind)
-            .field("source", source)
-            .field("indexedColumns", indexedColumns)
-
-          if (latestId.isDefined) {
-            builder.field("latestId", latestId.get)
-          }
-          optionalObjectField(builder, "options", options)
-          optionalObjectField(builder, "properties", properties)
-        }
-
-        // Add properties (schema) field
-        builder.field("properties", schema)
-      })
-    } catch {
-      case e: Exception =>
-        throw new IllegalStateException("Failed to jsonify Flint metadata", e)
-    }
-  }
 }
 
 object FlintMetadata {
 
-  /**
-   * Construct Flint metadata with JSON content, index settings, and latest log entry.
-   *
-   * @param content
-   *   JSON content
-   * @param settings
-   *   index settings
-   * @param latestLogEntry
-   *   latest metadata log entry
-   * @return
-   *   Flint metadata
-   */
-  def apply(
-      content: String,
-      settings: String,
-      latestLogEntry: FlintMetadataLogEntry): FlintMetadata = {
-    val metadata = FlintMetadata(content, settings)
-    metadata.copy(latestLogEntry = Option(latestLogEntry))
-  }
-
-  /**
-   * Construct Flint metadata with JSON content and index settings.
-   *
-   * @param content
-   *   JSON content
-   * @param settings
-   *   index settings
-   * @return
-   *   Flint metadata
-   */
-  def apply(content: String, settings: String): FlintMetadata = {
-    val metadata = FlintMetadata(content)
-    metadata.copy(indexSettings = Option(settings))
-  }
-
-  /**
-   * Parse the given JSON content and construct Flint metadata class.
-   *
-   * @param content
-   *   JSON content
-   * @return
-   *   Flint metadata
-   */
-  def apply(content: String): FlintMetadata = {
-    try {
-      val builder = new FlintMetadata.Builder()
-      parseJson(content) { (parser, fieldName) =>
-        {
-          fieldName match {
-            case "_meta" =>
-              parseObjectField(parser) { (parser, innerFieldName) =>
-                {
-                  innerFieldName match {
-                    case "version" => builder.version(FlintVersion.apply(parser.text()))
-                    case "name" => builder.name(parser.text())
-                    case "kind" => builder.kind(parser.text())
-                    case "source" => builder.source(parser.text())
-                    case "indexedColumns" =>
-                      parseArrayField(parser) {
-                        builder.addIndexedColumn(parser.map())
-                      }
-                    case "options" => builder.options(parser.map())
-                    case "properties" => builder.properties(parser.map())
-                    case _ => // Handle other fields as needed
-                  }
-                }
-              }
-            case "properties" =>
-              builder.schema(parser.map())
-            case _ => // Ignore other fields, for instance, dynamic.
-          }
-        }
-      }
-      builder.build()
-    } catch {
-      case e: Exception =>
-        throw new IllegalStateException("Failed to parse metadata JSON", e)
-    }
-  }
-
   def builder(): FlintMetadata.Builder = new Builder
 
   /**
@@ -231,16 +120,6 @@ object FlintMetadata {
       this
     }
 
-    def schema(schema: String): this.type = {
-      parseJson(schema) { (parser, fieldName) =>
-        fieldName match {
-          case "properties" => this.schema = parser.map()
-          case _ => // do nothing
-        }
-      }
-      this
-    }
-
     def latestLogEntry(entry: FlintMetadataLogEntry): this.type = {
       this.latestId = Option(entry.id)
       this.latestLogEntry = Option(entry)

flint-commons/src/main/scala/org/opensearch/flint/common/metadata/log/FlintMetadataLogEntry.scala

@@ -43,8 +43,8 @@ case class FlintMetadataLogEntry(
       state: IndexState,
       entryVersion: JMap[String, Any],
       error: String,
-      storageContext: JMap[String, Any]) = {
-    this(id, createTime, state, entryVersion.asScala.toMap, error, storageContext.asScala.toMap)
+      properties: JMap[String, Any]) = {
+    this(id, createTime, state, entryVersion.asScala.toMap, error, properties.asScala.toMap)
   }
 
   def this(
@@ -53,8 +53,8 @@ case class FlintMetadataLogEntry(
       state: IndexState,
       entryVersion: JMap[String, Any],
       error: String,
-      storageContext: Map[String, Any]) = {
-    this(id, createTime, state, entryVersion.asScala.toMap, error, storageContext)
+      properties: Map[String, Any]) = {
+    this(id, createTime, state, entryVersion.asScala.toMap, error, properties)
   }
 }
 

flint-commons/src/test/scala/org/opensearch/flint/common/metadata/FlintMetadataSuite.scala

@@ -0,0 +1,32 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.common.metadata
+
+import scala.collection.JavaConverters.mapAsJavaMapConverter
+
+import org.opensearch.flint.common.FlintVersion.current
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class FlintMetadataSuite extends AnyFlatSpec with Matchers {
+  "builder" should "build FlintMetadata with provided fields" in {
+    val builder = new FlintMetadata.Builder
+    builder.name("test_index")
+    builder.kind("test_kind")
+    builder.source("test_source_table")
+    builder.addIndexedColumn(Map[String, AnyRef]("test_field" -> "spark_type").asJava)
+    builder.schema(Map[String, AnyRef]("test_field" -> Map("type" -> "os_type").asJava).asJava)
+
+    val metadata = builder.build()
+
+    metadata.version shouldBe current()
+    metadata.name shouldBe "test_index"
+    metadata.kind shouldBe "test_kind"
+    metadata.source shouldBe "test_source_table"
+    metadata.indexedColumns shouldBe Array(Map("test_field" -> "spark_type").asJava)
+    metadata.schema shouldBe Map("test_field" -> Map("type" -> "os_type").asJava).asJava
+  }
+}

flint-core/src/main/scala/org/opensearch/flint/core/FlintClient.java

@@ -5,9 +5,7 @@
 
 package org.opensearch.flint.core;
 
-import java.util.Map;
-
-import org.opensearch.flint.core.metadata.FlintMetadata;
+import org.opensearch.flint.common.metadata.FlintMetadata;
 import org.opensearch.flint.core.storage.FlintWriter;
 
 /**
@@ -32,31 +30,6 @@ public interface FlintClient {
    */
   boolean exists(String indexName);
 
-  /**
-   * Retrieve all metadata for Flint index whose name matches the given pattern.
-   *
-   * @param indexNamePattern index name pattern
-   * @return map where the keys are the matched index names, and the values are
-   *         corresponding index metadata
-   */
-  Map<String, FlintMetadata> getAllIndexMetadata(String... indexNamePattern);
-
-  /**
-   * Retrieve metadata in a Flint index.
-   *
-   * @param indexName index name
-   * @return index metadata
-   */
-  FlintMetadata getIndexMetadata(String indexName);
-
-  /**
-   * Update a Flint index with the metadata given.
-   *
-   * @param indexName index name
-   * @param metadata  index metadata
-   */
-  void updateIndex(String indexName, FlintMetadata metadata);
-
   /**
    * Delete a Flint index.
    *

flint-core/src/main/scala/org/opensearch/flint/core/FlintOptions.java

@@ -95,7 +95,9 @@ public class FlintOptions implements Serializable {
 
   public static final String DEFAULT_BATCH_BYTES = "1mb";
 
-  public static final String CUSTOM_FLINT_METADATA_LOG_SERVICE_CLASS = "spark.datasource.flint.customFlintMetadataLogServiceClass";
+  public static final String CUSTOM_FLINT_METADATA_LOG_SERVICE_CLASS = "customFlintMetadataLogServiceClass";
+
+  public static final String CUSTOM_FLINT_INDEX_METADATA_SERVICE_CLASS = "customFlintIndexMetadataServiceClass";
 
   public static final String SUPPORT_SHARD = "read.support_shard";
 
@@ -189,6 +191,10 @@ public String getCustomFlintMetadataLogServiceClass() {
     return options.getOrDefault(CUSTOM_FLINT_METADATA_LOG_SERVICE_CLASS, "");
   }
 
+  public String getCustomFlintIndexMetadataServiceClass() {
+    return options.getOrDefault(CUSTOM_FLINT_INDEX_METADATA_SERVICE_CLASS, "");
+  }
+
   /**
    * FIXME, This is workaround for AWS OpenSearch Serverless (AOSS). AOSS does not support shard
    * operation, but shard info is exposed in index settings. Remove this setting when AOSS fix

flint-core/src/main/scala/org/opensearch/flint/core/MetaData.scala

@@ -5,8 +5,6 @@
 
 package org.opensearch.flint.core
 
-import org.opensearch.flint.core.metadata.FlintMetadata
-
 /**
  * OpenSearch Table metadata.
  *
@@ -18,11 +16,3 @@ import org.opensearch.flint.core.metadata.FlintMetadata
  *   setting
  */
 case class MetaData(name: String, properties: String, setting: String)
-
-object MetaData {
-  def apply(name: String, flintMetadata: FlintMetadata): MetaData = {
-    val properties = flintMetadata.getContent
-    val setting = flintMetadata.indexSettings.getOrElse("")
-    MetaData(name, properties, setting)
-  }
-}